In recent years, capacitive microphones, due to their low price and excellent performance, have been widely applied in electronic products such as cell phones and earphones. The critical element for a capacitive microphone is a capacitor component comprised of polar plates, a vibrating diaphragm and a spacer provided therebetween.
The spacer in a capacitive microphone mainly functions to isolate polar plates and the vibrating diaphragm to form a parallel plate capacitor. Generally, the spacer may be fabricated in advance, that is, the spacer is formed as a single separate ring sheet by punching and cutting and then mounted into the capacitive microphone. In some product structures, it is also possible to mount spacers that are not separated into a plurality of capacitive microphones arranged in an array and then separate them by punching and cutting. For example, the patent application No. CN200610099179.6 discloses a structure in which parts of multiple capacitive microphones are arranged in array and then cut separate after being assembled together, which teaches that the spacer is made from resin film or metal sheet.
However, if the spacer is made from resin film, the low cost and easy fabrication can be obtained, but static electricity may be easily produced during separation process, which causes impact on product performance. Furthermore, if the spacer is made from a metal sheet, the above electro-static problem may be solved, however, both the fabrication difficulty and costs are increased. Further, parasitic capacitance between polar plates and vibrating diaphragm is increased, and the sensibility limit of products is deteriorated. Therefore, it is needed for a capacitive microphone that is of low cost, simple structure and able to mitigate electrostatic influence.